Latest Android Version

I recently cracked my work-issued S4 and was issued this Droid Incredible as a temporary replacement (as you can see by my username, I am not very happy about this). Anyway, I noticed the software version of this phone is 4.0.4 (Ice Cream Sandwich). Does anyone know the latest version of Android this phone can support? I already did the OTA and it looks like I am up to date but I just want to make sure. Is there a way (whether rooted or not) to manually install a newer version (up to and including KitKat).